The present invention relates to a method and device for cutting and friction-stir-welding of metal material. For example, the present invention is preferably applied to the machining and assembling of mechanical parts or structural parts.
When machining and assembling mechanical parts or structural parts and the like, separate machining devices are used; for example, a cutting machine tool is used for the cutting process, and various welding/bonding devices are used for the assembling process.
Compound machining carried out by a single cutting machine tool usually involves a combination of cutting processes, such as turning and rotary tool machining using a compound engine lathe, or a rotary tool machining and bite machining using a machining center. One example of a combination of a cutting process with another process is the combination of rotary tool machining and laser hardening.
One example of a method of joining members is friction stir welding (refer to Japanese Patent Laid-Open Publication No. 11-90655, U.S. Pat. No. 6,050,474). The method includes inserting a round shaft (called a rotary tool) into a joint portion between members to be joined, and rotating and moving the rotary tool along the joint portion, thereby heating, mobilizing and plasticizing the material to effect solid-phase welding the joint portion. The rotary tool comprises a small-diameter portion (called a pin) to be inserted into the joint portion, and a large-diameter portion (called a shoulder) positioned to the exterior. The small-diameter portion and the large-diameter portion are coaxial. The large-diameter-portion is coupled to a drive so as to be rotated. The joint portion is provided with a raised portion.
Further, as disclosed in Japanese Patent Laid-Open Publication No. 9-508073 (EP0752926B1), the rotary tool is tilted when being inserted into the welding joint so that the small-diameter portion of the rotary tool is angled and leads the large-diameter portion in the direction of movement of the tool. In other words, the rotary tool is tilted rearwards.
As explained above, no conventional machining device is designed and manufactured to carry out both cutting and welding using a single machining device.
Therefore, in order to carry out both a cutting process and a welding process, two separate machining devices, i.e. a cutting device and a bonding device, are needed. This leads to problems, such as a high equipment cost, a large installation space, a large plant building, a long lead time caused by the waiting time between the cutting process and the bonding process, and the need to provide operators for the cutting and bonding processes.
The present invention aims at providing a compound machining device which is capable of carrying out the cutting and bonding processes using a single device.
The object of the present invention is achieved by a device comprising linear movement devices capable of moving in directions X, Y, and Z, respectively; rotary devices capable of rotation about axes A and B, respectively; a control unit capable of simultaneously controlling the five coordinate systems; a main shaft for rotating a tool; a storage device for storing a plurality of tools for the main shaft; and an exchange device for exchanging tools between the main shaft and the storage device; wherein the storage device is capable of storing a cutting tool and a friction stir welding tool; and the control unit mounts either the cutting tool or the friction stir welding tool to the main shaft from the storage device using the exchange device based on a program, and performs machining using the tool mounted to the main shaft.